The 55-year-old singer had breast cancer 10 years ago and says it made her stop and think about what she actually wanted in life, leading to the adoption of her two sons, Wyatt, nine and Levi, six.

She explained to Event magazine: ''It took the whole cancer thing for me to look at my life and go 'what did I think my life was going to look like?' I thought I was going to get married and have kids because that's what my parents did. But I never thought I was going to have cancer. And I also didn't think I was going to become a well-known rock star and travel the world.

''So, after I had cancer I thought I can be a mum - and if a great man comes in and becomes a part of that story, fantastic. But I'm probably not gonna get married and have children in that order. So, let's start the process and see what happens.''

In 2012 doctors also discovered Sheryl had a benign brain tumour and she has scans every two years to keep tabs on it.

She said: ''I just had one, it's all good, hadn't grown. Well, a minuscule amount but nothing more. I use it now and again as an excuse for my bad memory.''

Although Sheryl has been unlucky in love, with failed relationships with Eric Clapton, Lance Armstrong and Owen Wilson, she still holds out hope that she will meet 'The One'.

She said: ''I wouldn't say I've sacrificed [a relationship for a career]. I would just say I was just unsuccessful. It took me a long time to learn what it means to be authentic and intimate with someone - and I don't mean sexually. But to let your guard down and speak your truth and let the chips fall where they may. You have to have that in a relationship. I'm still learning.

''I love being in a relationship. I would love to be in relationship now. I'd love for my kids to witness what a successful loving relationship looks like. But I'm not dead, so I don't think it's impossible! I'm just a work in progress.''